1. Field of the Invention
This invention relates to a flashing for sealing between a waterproof roofing membrane and a vertical wall such as the parapet wall surrounding flat industrial roofs. More particularly, this invention relates to a flashing which may be installed before the roofing membrane is installed and which facilitates rapid connection to form a watertight seal between the roofing membrane and the wall.
2. Related Art
Waterproof roofing membranes are commonly used to provide a long-lasting leakproof roof, particularly for flat or mildly sloped roofs such as are found on warehouses, factories, supermarkets, malls and other large commercial and industrial buildings. To increase safety for individuals who may be required to work on the flat roof, the perimeter of the roof on such structures is often surrounded by a low parapet wall. However, such a wall presents difficulties when installing the roofing membrane. Even where the roofing membrane is unbroken, wind-driven rain and snow may enter gaps between the wall and the membrane when installed with prior art methods.
Previously, roofing membranes have been connected to the vertical wall by bringing the membrane up the parapet wall from the roof to a height above that of snow accumulation and fastening it at intervals by screws, nails or the like, either directly through the membrane or more commonly through a stiffener, such as a strip of rigid material.
In order to obtain a good waterproof seal between the membrane and the vertical wall, the fasteners must be very closely spaced. Not only is it time consuming to apply the required number of fasteners, but even when stiffeners are used, after a period of time, the weight of the membrane and the effects of wind and vibration may cause a small gap to appear between the connection points which permits rain to enter between the face of the vertical wall and the roofing membrane.
Moreover, with previous installation methods the fasteners must be applied through the roofing membrane which means that the membrane must be punctured and that this step must occur at the same time that the roofing membrane is being installed. If a stiffener is used, both the stiffener and the membrane must simultaneously be held in position against the wall and in the correct relationship as the fasteners are applied.
Using such methods, it has been difficult to obtain the proper alignment of the membrane on the roof with the stiffener and the membrane against the vertical wall, and to apply the fasteners to make a permanent connection. Once installed, the fasteners penetrate the membrane and further adjustments of the position of the membrane are difficult.
A further problem with previous methods has been that individual fasteners, such as the screws or nails used to attach the membrane to the parapet wall, are occasionally dropped between the membrane and the parapet wall during installation of the membrane. Ultimately, the sharp surfaces on such trapped fasteners may puncture the membrane leading to leaks.
In contrast, with the present invention the flashing is installed at any convenient time, for example when the parapet wall is being constructed. This allows the work of installing the membrane to proceed without interfering with the installation of the membrane, and any misplaced fasteners used in installing the flashing of this invention may be cleared away, and are not likely to be trapped underneath the membrane.
When the membrane is to be installed, it can temporarily be held in the flashing of this invention while the roofing membrane is adjusted, wrinkles and pockets smoothed out, and cuts made for roof openings, etc. Because the temporary hold does not damage the membrane, if necessary, the membrane may be shifted in the flashing. Once the proper alignment of all parts of the membrane has been achieved, the temporary connection may rapidly be made more secure using a punch to bend tabs which hold the membrane to the flashing. However, the tabs may later be unbent to remove the membrane for repair or replacement, or to access the roof underneath. The tabs permit the membrane to be installed without using separate fasteners which slow the operation and risk damage to the waterproof integrity of the membrane.
In one form, the flashing may be installed when a brick and mortar wall is constructed. In an alternative form, the flashing may be installed to an existing vertical wall. In either case, it may be installed well in advance of the roofing membrane.
The roofing membrane flashing of this invention is designed to permit an extremely rapid connection between the roofing membrane and a vertical wall to produce the desired watertight seal. Moreover, the design of the present invention completely covers the gap between the roofing membrane and the face of the vertical wall so that spaces do not develop over time between the wall and the membrane.
Accordingly, one object of the present invention is to provide a flashing which may be installed prior to the installation of the roofing membrane. A second object of the invention is to provide a roofing membrane flashing which may be installed in a brick and mortar wall at the time the wall is to be constructed. Yet another object of the invention is to provide a flashing which requires no separate fasteners to be handled when the membrane is attached. Still another object of the invention is to provide a flashing system which may be formed from an initially flat sheet stock material by bending. A further object of the invention is to provide a corner piece to provide a simple seal between two flashings at an inside or outside corner. Yet another object is to provide a flashing which will provide a first temporary non-damaging grip on the membrane which may be adjusted before making the seal permanent.